Guidewire exchange catheter

ABSTRACT

A catheter for facilitating the exchange of guidewires during the course of a transluminal angioplasty or related procedure which comprises an elongated, flexible, tubular member having at least one lumen running the full length thereof from its proximal end to its distal end and with at least three apertures or ports extending through the wall thereof at longitudinally spaced locations near the distal end of the tubular member. These ports communicate with the lumen of the tubular member and a longitudinal slit is also provided through the wall of the tubular member connecting the most proximal port to the next proximal port. The exchanger catheter may also include a proximal hub connected to the proximal end of the elongated plastic tube.

BACKGROUND OF THE INVENTION

I. Field of the Invention:

This invention relates generally to catheter apparatus for carrying outa variety of medical procedures and more particularly to an exchangecatheter for facilitating the exchange of one catheter guidewire foranother when required for effectively carrying out the catheterizationprocedure.

II. Discussion of the Prior Art:

Since its introduction in the mid-1970's by Dr. Andreas Gruentzig,coronary transluminal angioplasty, using a balloon catheter, has becomea recognized method for treating obstructed coronary blood vessels. Incarrying out this procedure, an incision may typically be made in thepatient's thigh to gain access to the femoral artery and an introduceris inserted into the wound. Next, a guiding catheter is passed throughthe introducer and routed through the vascular system until the distalend of the guiding catheter reaches the coronary ostium. Following that,a flexible guidewire is inserted through the guiding catheter until itsdistal end exits the distal end of the guiding catheter. The surgeon, bymanipulating the proximal end of the guidewire, attempts to pass itacross the stenotic lesion which is obstructing the coronary artery tobe treated. Once the guidewire has been made to cross the lesion, aballoon angioplasty catheter is passed over the guidewire by insertingthe proximal end of the guidewire into the distal end of the ballooncatheter and then pushing the balloon catheter over the guidewire untilthe balloon on the distal end of the balloon catheter is adjacent thelesion to be treated. Once so positioned, the balloon is inflated tothereby press the stenotic lesion against the wall of the blood vesseland restoring patency to the treated blood vessel.

The above-described procedure assumes the use of a so-calledover-the-wire balloon angioplasty catheter. A more recent innovation isthe so-called Monorail catheter in which only a small distal segment ofthe balloon catheter actually passes over the guidewire with theremaining portion of the guidewire then extending generally along theexterior wall of the balloon catheter in the proximal direction. TheMonorail catheter and its use is more particularly described in theBonzel U.S. Pat. No. 4,762,129.

It frequently occurs during the conduct of a balloon angioplastyprocedure that an originally selected guidewire may turn out not to besuitable for easily passing the stenotic lesion. It thus often becomesnecessary to substitute an alternate guidewire. For example, to arriveat the site of the lesion, it may be necessary to employ a guidewirehaving a particular shape configuration on its distal end. However, withthe guidewire so shaped, it may not easily traverse the lesion once thesite is arrived at. Thus, the first catheter guidewire must be withdrawnand replaced with a second whose tip may more readily traverse thelesion.

The present invention is directed to a special purpose catheter forfacilitating the exchange of guidewires used in angiography and/orangioplasty procedures using the Monorail™ catheter system. The exchangecatheter is so designed that it can be used to transport the distal endportion of a new guidewire to the location within the vascular systemreached by the distal end of the first guidewire by using the firstguidewire as the rail along which the exchange catheter is routed. Oncethis maneuver has been accomplished, the first guidewire may be strippedout of the exchange catheter and the guide catheter containing it. Then,the exchange catheter itself can be withdrawn from the guide catheterwithout disturbing the replacement guidewire.

It is accordingly a principal object of the present invention to providea new surgical tool for facilitating the conduct of transluminalangioplasty and/or angiography procedures.

Another object of the invention is to provide a surgical implement forfacilitating the exchange of guidewires used during angiographic andangioplasty procedures.

Still another object of the invention is to provide an exchange catheterfor use in a Monorail™ system for allowing a first selected guidewire tobe replaced with a second guidewire without losing the positionaladvantage gained during the installation of the first guidewire. That isto say, using the apparatus and procedure of the present invention, itis no longer necessary to strip out the first guidewire from the guidecatheter before the new guidewire is installed to the point where itsdistal end is at the location occupied by the distal end of the firstguidewire before it is withdrawn.

SUMMARY OF THE INVENTION

The foregoing objects and advantages of the present invention areachieved by providing an exchange catheter having elongated flexibleplastic tubular member whose outside dimensions permit it to be readilyinserted through the lumen of a guide catheter. Located just proximal ofthe distal end of the tubular member are three longitudinally spacedports which extend through the wall of the tubular member so as tocommunicate with the central lumen. A longitudinal slit is also formedthrough the wall of the tubular member extending from the most proximalport to the second most proximal port.

When, during the course of a surgical catheterization procedure, it isdesired to replace an existing guidewire whose tip had been advanced toa predetermined site beyond the distal end of a guide catheter, thedistal end of the replacement or second guidewire is fed through themost distal port of the exchange catheter and advanced through theexchange catheter until its distal end is at the distal end of theexchange catheter. Next, the proximal end of the first guidewire isthreaded into the distal end of the exchange catheter and out from themost distal port. While gripping the original or first guidewire nearits proximal end, the physician advances the exchange catheter into theproximal end of the guide catheter and along the first guidewire untilthe distal end of the exchange catheter reaches the distal end of thefirst guidewire. As the exchange catheter is so advanced through theguide catheter, it carries the replacement or second guidewire alongwith it. The surgeon may now hold the proximal end of the exchangecatheter against longitudinal movement as he strips the originalguidewire out of the guide catheter. At this point, the distal end ofthe exchange catheter and the distal end of the replacement or secondguidewire remain at the former location of the distal end of the firstguidewire.

Now, by holding the second guidewire at its proximal end to preventlongitudinal movement thereof, the surgeon may now strip back theexchange catheter which will ride along the replacement guidewire, theguidewire fitting through the longitudinal slit provided between themost distal and second-most distal ports in the exchange catheter.

When the exchange catheter has been withdrawn from the guide catheter tothe point where the second-most distal or middle port becomes visiblewith the second guidewire extending out of it, the surgeon may readilystrip the remaining few inches of the exchange catheter off from theproximal end of the guidewire leaving only the guidewire in positionwithin the lumen of the guide catheter. This completes the exchangeprocedure and the surgeon may continue on with the remainder of theparticular catheterization procedure which is underway.

DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention willbecome more apparent to those skilled in the art from the followingdetailed description of a preferred embodiment, especially whenconsidered in conjunction with the accompanying drawings in which likenumerals in the several views refer to correspondingly parts.

FIG. 1 is a side elevational view of the exchange catheter of thepresent invention;

FIG. 1A is a cross-sectional view taken along line 1a--1a in FIG. 1.

FIGS. 2A through 2F are a series of side elevational views, partially incross-section, helpful in understanding the way in which the exchangecatheter of FIG. 1 is used; and

FIG. 3 is a cross-sectional view of an alternative, bi-lumen exchangecatheter taken at the same location as the cross-sectional view of FIG.1A.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 1A, there is indicated generally by numeral 10the exchange catheter of the present invention. It is seen to include anelongated, flexible, plastic, tubular member 12 having a proximal end 14and a distal end 16 and with at least one internal lumen 18 (FIG. 1A)extending the entire length thereof. A further lumen (not shown) may beprovided for allowing distal dye injection for visualizing the treatmentsite. The tubular member 12 is preferably formed from any one of anumber of medical grade plastics commonly used in the fabrication ofintravascular catheters and including, for example, polyurethane,polyethylene, tetrafluoroethylene fluorocarbon polymer and nylon.Without limitation, the exchange catheter may typically have an outsidediameter of about 1.2 mm and an internal diameter of 0.8 mm. As willbecome more apparent as the description of the preferred embodimentprogresses, the outside diameter of the exchange catheter 10 must besufficiently small so as to be able to readily pass through the lumen ofa guide catheter. The internal diameter of the lumen 18 of the exchangecatheter must be sufficiently large to permit two guidewires to passthere along.

With continued reference to FIG. 1, it can be seen that toward thedistal end 16 of the exchange catheter, there is provided a series ofthree longitudinally spaced ports, the most proximal being identified bynumeral 20, the next most proximal by numeral 22 and the most distal bynumeral 24. These ports pass entirely through the side wall of thetubular member 12 so as to communicate with the lumen 18. As is shown inthe cross-sectional view of FIG. 1A, a longitudinal slit 26 extendsthrough the thickness of the wall between the most proximal port 20 andthe second-most proximal port 22.

Affixed to the proximal end 14 of the tubular member 12 is a moldedplastic hub 28 of a conventional design.

Having described the physical construction of the exchange catheter ofthe present invention, there will next be provided a detailedexplanation of the manner in which it is used to effect a substitutionof a second guidewire for a first during the course of a diagnostic orangioplasty procedure. In this regard, reference will be made to theseries of views labeled FIGS. 2A through 2F.

Referring first to FIG. 2A, numeral 30 is used to identify the walls ofa blood vessel, such as a coronary artery, which is partially plugged bya stenotic lesion 32 to be treated. Using the Seldinger technique, anincision is made in the patient's leg to gain access to the femoralartery and a guide catheter 34 has been advanced through an introducer(not shown) and routed through the vascular system to the coronaryostium. Following that, a first guidewire, here identified by numeral36, has been fed through the guide catheter 34, but upon reaching thesite of the stenotic lesion 32, it was determined that the type ofdistal tip configuration on the guidewire 36 would not allow it to passthrough the constriction in the blood vessel defined by the stenoticlesion 32. Hence, the surgeon has decided to substitute a secondguidewire 38 having a different distal tip configuration thought to besuitable for crossing the stenotic lesion 32.

To avoid the necessity of totally withdrawing the first guidewire 36 andstarting over, in accordance with the present invention, the exchangecatheter 10 is brought into play in the following manner. As a firststep, the distal end portion of the replacement guidewire 38 is threadedthrough the most proximal port 20 located near but proximal to thedistal end of the exchange catheter 10 and advanced until its distal endprotrudes slightly beyond the distal end 16 of the exchange catheter.Next, the proximal end of the original guidewire 36 is threaded throughthe lumen 18 of the exchange catheter at its distal end 16 and made topass outwardly therefrom through the distal port 24.

The surgeon next pushes the exchange catheter 10 in the distal directionalong the original guidewire 38 and through the lumen of the guidecatheter 34 while holding on to the proximal end of the guidewire 38 toprevent its movement. When the distal tip 16 of the exchange catheter isclose to the distal end of the first guidewire 36 in the coronary arterybeing treated, as shown in FIG. 2B, the surgeon pulls back on theoriginal guidewire 36 completely removing it from the exchange catheterand guide catheter while leaving the replacement guidewire 38 near or atthe site of the lesion. See FIG. 2C.

The next step is to remove the exchange catheter 10 from the newguidewire 38 so as to leave it by itself within the lumen of the guidecatheter 34. To do this, the surgeon grips the proximal end of theguidewire 38 while pulling back on and thereby peeling the exchangecatheter 10 from guidewire 38. During this step, and as illustrated inFIG. 2D, the guidewire 38 passes through the slit 18 formed through thewall of the exchange catheter 10 between the ports 20 and 22. Thisprocedure leaves the distal end of the replacement guidewire 38 at ornear the site of the lesion 32 which had earlier been approached by theoriginal guidewire 36.

The step of pulling and peeling the exchange catheter 10 relative to thereplacement guidewire 38 continues until port 22 in the exchangecatheter becomes visible as it exits the proximal hub of the guidecatheter 34. When the exchange catheter has been peeled to the pointwhere the guidewire 38 is exiting the exchange catheter 10 at port 22(FIG. 2E), the surgeon discontinues the peeling action and then proceedsto pull the remaining relatively short distal end portion of theexchange catheter from the proximal end of the guide catheter. Thesurgeon may then readily strip the remaining portion of the exchangecatheter free from the guidewire 38, completing the guidewire exchangeprocedure as reflected in the view of FIG. 2F.

Using the procedure and exchange catheter of the present invention, aguidewire substitution can be made without the need for an extensionwire which had heretofore been required when using over-the-wirecatheter technology. The surgeon may readily change one type ofguidewire for another, either to alter the maneuverability of the distalend thereof or to provide a different type of distal tip on theguidewire allowing it to pass across a serious blood vessel obstruction.The use of the exchange catheter will maintain the position achievedwhile using a first guidewire relative to the lesion being treated, butallowing the substitution of a second guidewire for the first. Forexample, if it is assumed that the first guidewire is in the distalcoronary artery but manipulation of that guidewire does not result insteering it down a torturous distal path, instead of pulling the firstguidewire and losing position in the artery, the exchange catheter 10 ofthe present invention is fed down the first guidewire 36, carrying a newtype of guidewire. Once the exchange catheter is close to the distal tipof the first guidewire, the first guidewire can be removed, followed bythe removal of the exchange itself leaving the replacement guidewire atthe desired location.

It has also been found expedient to utilize an exchange catheter havingtwo lumens as is illustrated in the cross-sectional view of FIG. 3.Again, the lumen 18 is used to receive the guidewires 36 and 38 whilethe additional lumen 40 is available to allow pressure measurements tobe taken both proximal and distal to the lesion being treated whereby anaccurate pressure gradient can be measured to assess the efficacy of theballoon angioplasty procedure. The lumen 40 may also be used to inject acontrast medium for visualizing the site being treated or,alternatively, to profuse blood or other nutrient to the site of thelesion.

This invention has been described herein in considerable detail in orderto comply with the Patent Statutes and to provide those skilled in theart with the information needed to apply the novel principles and toconstruct and use such specialized components as are required. However,it is to be understood that the invention can be carried out byspecifically different equipment and devices, and that variousmodifications, both as to the equipment details and operatingprocedures, can be accomplished without departing from the scope of theinvention itself.

What is claimed is:
 1. A guidewire exchange catheter for facilitatingthe substitution of a first guidewire for a second guidewire,comprising(a) first and second elongated flexible guidewires; and (b) anelongated flexible plastic tubular member having a proximal end and adistal end with a first lumen extending the entire length thereof andhaving at least three spaced-apart apertures longitudinally aligned arelatively short distance from said distal end and extending through theside wall of said tubular member to said first lumen for receiving saidfirst and second guidewires therethrough, with a slit extending throughsaid wall to said first lumen and extending between the most proximaland second-most proximal ones of said spaced-apart apertures.
 2. Theguidewire exchange catheter as in claim 1 and further including afurther lumen extending the entire length of said tubular member andgenerally parallel to said first lumen.